Forecasting the Seas

Shipping companies can route ships more safely and efficiently. Ocean search-and-rescue can operate more effectively. Meteorologists and climatologists now have a tool to provide long-range weather prediction more accurately. Navies too can perform more accurate anti-submarine surveillance. And environmental managers now have a mechanism to track pollution, algal blooms, or emergent situations such as oil spills. And, this is all due to a unique three-dimensional ocean model that has been developed by Rosenstiel School researchers in collaboration with scientists at the Naval Research Laboratory.

Featured in the March issue of Oceanography, the HYbrid Coordinate Ocean Model (HYCOM) is the critical part of data assimilative systems at the Naval Research Laboratory and at NOAA’s National Center for Environmental Prediction. The Navy will tap the velocities, temperature, and salinities of the HYCOM prediction system to force smaller models that provide even higher resolution that can account for things like rivers, tides, etc. in real-time for anywhere in the world. NOAA’s new Real-Time Ocean Forecast System will provide mariners with “nowcasts” and five-day forecasts for the entire North Atlantic Ocean. While other ocean models have been developed in the past, HYCOM is unique not only because it provides three-dimensional, global data that is of fine enough resolution to factor in the real-time displacements in currents caused by eddies, but also because of its flexibility in modeling both coastal and deep ocean regions (http://www.hycom.org). This enhanced understanding of the ocean offers invaluable applications.

“While a computer model may sound rather abstract to non-scientists, it’s exactly what can help clarify forecasting and minimize or prevent impacts from natural hazards on the seas,” said Dr. Eric Chassignet, principal investigator and a Rosenstiel School professor in meteorology and physical oceanography. Chassignet also just published a related book, titled Ocean Weather Forecasting: An Integrated View of Oceanography, which is now available.

Scientists often develop computer models to fill in the gaps where they cannot make real-world observations of natural phenomenon. In the case of ocean processes, however, modelers start with fluid dynamics that are the laws of physics that explain how fluid – and in this case, the ocean – responds to different variables. All fluids obey these same laws of physics, and so the researchers end up with a variety of equations that can be simplified to create simple ocean models or made very complex as the scientists try to expand time and space constraints. The HYCOM model will help forecasters and others understand the ocean’s currents, temperature, salinity, and other variables better.

“The broad partnership of institutions that is collaborating to develop and demonstrate the performance and applications of HYCOM has already been able to produce realistic imagery in real-time on ocean basin-scales (and soon to be global) in hindcast, nowcast, and prediction modes,” Chassignet said. He authored the Oceanography article with Dr. George Halliwell and Dr. Ashwanth Srinivasan, also scientists at the Rosenstiel School, and representation from the Navy Research Laboratory, NOAA, and the University of North Carolina.

Rosenstiel School is part of the University of Miami and, since its founding in the 1940s, has grown into one of the world’s premier marine and atmospheric research institutions.